2 ctdb_call protocol code
4 Copyright (C) Andrew Tridgell 2006
6 This library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 3 of the License, or (at your option) any later version.
11 This library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public
17 License along with this library; if not, see <http://www.gnu.org/licenses/>.
20 see http://wiki.samba.org/index.php/Samba_%26_Clustering for
21 protocol design and packet details
24 #include "lib/events/events.h"
25 #include "lib/tdb/include/tdb.h"
26 #include "system/network.h"
27 #include "system/filesys.h"
28 #include "../include/ctdb_private.h"
31 find the ctdb_db from a db index
33 struct ctdb_db_context *find_ctdb_db(struct ctdb_context *ctdb, uint32_t id)
35 struct ctdb_db_context *ctdb_db;
37 for (ctdb_db=ctdb->db_list; ctdb_db; ctdb_db=ctdb_db->next) {
38 if (ctdb_db->db_id == id) {
47 local version of ctdb_call
49 int ctdb_call_local(struct ctdb_db_context *ctdb_db, struct ctdb_call *call,
50 struct ctdb_ltdb_header *header, TDB_DATA *data,
53 struct ctdb_call_info *c;
54 struct ctdb_registered_call *fn;
55 struct ctdb_context *ctdb = ctdb_db->ctdb;
57 c = talloc(ctdb, struct ctdb_call_info);
58 CTDB_NO_MEMORY(ctdb, c);
61 c->call_data = &call->call_data;
62 c->record_data.dptr = talloc_memdup(c, data->dptr, data->dsize);
63 c->record_data.dsize = data->dsize;
64 CTDB_NO_MEMORY(ctdb, c->record_data.dptr);
69 for (fn=ctdb_db->calls;fn;fn=fn->next) {
70 if (fn->id == call->call_id) break;
73 ctdb_set_error(ctdb, "Unknown call id %u\n", call->call_id);
79 ctdb_set_error(ctdb, "ctdb_call %u failed\n", call->call_id);
84 if (header->laccessor != caller) {
87 header->laccessor = caller;
90 /* we need to force the record to be written out if this was a remote access,
91 so that the lacount is updated */
92 if (c->new_data == NULL && header->laccessor != ctdb->vnn) {
93 c->new_data = &c->record_data;
97 if (ctdb_ltdb_store(ctdb_db, call->key, header, *c->new_data) != 0) {
98 ctdb_set_error(ctdb, "ctdb_call tdb_store failed\n");
105 call->reply_data = *c->reply_data;
106 talloc_steal(ctdb, call->reply_data.dptr);
107 talloc_set_name_const(call->reply_data.dptr, __location__);
109 call->reply_data.dptr = NULL;
110 call->reply_data.dsize = 0;
112 call->status = c->status;
122 static void ctdb_send_error(struct ctdb_context *ctdb,
123 struct ctdb_req_header *hdr, uint32_t status,
124 const char *fmt, ...) PRINTF_ATTRIBUTE(4,5);
125 static void ctdb_send_error(struct ctdb_context *ctdb,
126 struct ctdb_req_header *hdr, uint32_t status,
127 const char *fmt, ...)
130 struct ctdb_reply_error *r;
135 msg = talloc_vasprintf(ctdb, fmt, ap);
137 ctdb_fatal(ctdb, "Unable to allocate error in ctdb_send_error\n");
141 msglen = strlen(msg)+1;
142 len = offsetof(struct ctdb_reply_error, msg);
143 r = ctdb->methods->allocate_pkt(msg, len + msglen);
144 CTDB_NO_MEMORY_FATAL(ctdb, r);
145 talloc_set_name_const(r, "send_error packet");
147 r->hdr.length = len + msglen;
148 r->hdr.ctdb_magic = CTDB_MAGIC;
149 r->hdr.ctdb_version = CTDB_VERSION;
150 r->hdr.operation = CTDB_REPLY_ERROR;
151 r->hdr.destnode = hdr->srcnode;
152 r->hdr.srcnode = ctdb->vnn;
153 r->hdr.reqid = hdr->reqid;
156 memcpy(&r->msg[0], msg, msglen);
158 ctdb_queue_packet(ctdb, &r->hdr);
165 send a redirect reply
167 static void ctdb_call_send_redirect(struct ctdb_context *ctdb,
168 struct ctdb_req_call *c,
169 struct ctdb_ltdb_header *header)
171 struct ctdb_reply_redirect *r;
173 r = ctdb->methods->allocate_pkt(ctdb, sizeof(*r));
174 CTDB_NO_MEMORY_FATAL(ctdb, r);
175 talloc_set_name_const(r, "send_redirect packet");
176 r->hdr.length = sizeof(*r);
177 r->hdr.ctdb_magic = CTDB_MAGIC;
178 r->hdr.ctdb_version = CTDB_VERSION;
179 r->hdr.operation = CTDB_REPLY_REDIRECT;
180 r->hdr.destnode = c->hdr.srcnode;
181 r->hdr.srcnode = ctdb->vnn;
182 r->hdr.reqid = c->hdr.reqid;
183 r->dmaster = header->dmaster;
185 ctdb_queue_packet(ctdb, &r->hdr);
191 send a dmaster request (give another node the dmaster for a record)
193 This is always sent to the lmaster, which ensures that the lmaster
194 always knows who the dmaster is. The lmaster will then send a
195 CTDB_REPLY_DMASTER to the new dmaster
197 static void ctdb_call_send_dmaster(struct ctdb_db_context *ctdb_db,
198 struct ctdb_req_call *c,
199 struct ctdb_ltdb_header *header,
200 TDB_DATA *key, TDB_DATA *data)
202 struct ctdb_req_dmaster *r;
203 struct ctdb_context *ctdb = ctdb_db->ctdb;
206 len = offsetof(struct ctdb_req_dmaster, data) + key->dsize + data->dsize;
207 r = ctdb->methods->allocate_pkt(ctdb, len);
208 CTDB_NO_MEMORY_FATAL(ctdb, r);
209 talloc_set_name_const(r, "send_dmaster packet");
211 r->hdr.ctdb_magic = CTDB_MAGIC;
212 r->hdr.ctdb_version = CTDB_VERSION;
213 r->hdr.operation = CTDB_REQ_DMASTER;
214 r->hdr.destnode = ctdb_lmaster(ctdb, key);
215 r->hdr.srcnode = ctdb->vnn;
216 r->hdr.reqid = c->hdr.reqid;
218 r->dmaster = c->hdr.srcnode;
219 r->keylen = key->dsize;
220 r->datalen = data->dsize;
221 memcpy(&r->data[0], key->dptr, key->dsize);
222 memcpy(&r->data[key->dsize], data->dptr, data->dsize);
224 /* XXX - probably not necessary when lmaster==dmaster
225 update the ltdb to record the new dmaster */
226 header->dmaster = r->hdr.destnode;
227 ctdb_ltdb_store(ctdb_db, *key, header, *data);
229 ctdb_queue_packet(ctdb, &r->hdr);
236 called when a CTDB_REQ_DMASTER packet comes in
238 this comes into the lmaster for a record when the current dmaster
239 wants to give up the dmaster role and give it to someone else
241 void ctdb_request_dmaster(struct ctdb_context *ctdb, struct ctdb_req_header *hdr)
243 struct ctdb_req_dmaster *c = (struct ctdb_req_dmaster *)hdr;
244 struct ctdb_reply_dmaster *r;
245 TDB_DATA key, data, data2;
246 struct ctdb_ltdb_header header;
247 struct ctdb_db_context *ctdb_db;
252 key.dsize = c->keylen;
253 data.dptr = c->data + c->keylen;
254 data.dsize = c->datalen;
256 ctdb_db = find_ctdb_db(ctdb, c->db_id);
258 ctdb_send_error(ctdb, hdr, -1,
259 "Unknown database in request. db_id==0x%08x",
264 /* fetch the current record */
265 ret = ctdb_ltdb_lock_fetch_requeue(ctdb_db, key, &header, hdr, &data2,
266 ctdb_recv_raw_pkt, ctdb);
268 ctdb_fatal(ctdb, "ctdb_req_dmaster failed to fetch record");
272 DEBUG(2,(__location__ " deferring ctdb_request_dmaster\n"));
276 /* its a protocol error if the sending node is not the current dmaster */
277 if (header.dmaster != hdr->srcnode &&
278 hdr->srcnode != ctdb_lmaster(ctdb_db->ctdb, &key)) {
279 ctdb_fatal(ctdb, "dmaster request from non-master");
283 header.dmaster = c->dmaster;
284 ret = ctdb_ltdb_store(ctdb_db, key, &header, data);
285 ctdb_ltdb_unlock(ctdb_db, key);
287 ctdb_fatal(ctdb, "ctdb_req_dmaster unable to update dmaster");
291 /* put the packet on a temporary context, allowing us to safely free
292 it below even if ctdb_reply_dmaster() has freed it already */
293 tmp_ctx = talloc_new(ctdb);
295 /* send the CTDB_REPLY_DMASTER */
296 len = offsetof(struct ctdb_reply_dmaster, data) + data.dsize;
297 r = ctdb->methods->allocate_pkt(tmp_ctx, len);
298 CTDB_NO_MEMORY_FATAL(ctdb, r);
300 talloc_set_name_const(r, "reply_dmaster packet");
302 r->hdr.ctdb_magic = CTDB_MAGIC;
303 r->hdr.ctdb_version = CTDB_VERSION;
304 r->hdr.operation = CTDB_REPLY_DMASTER;
305 r->hdr.destnode = c->dmaster;
306 r->hdr.srcnode = ctdb->vnn;
307 r->hdr.reqid = hdr->reqid;
308 r->datalen = data.dsize;
309 memcpy(&r->data[0], data.dptr, data.dsize);
311 ctdb_queue_packet(ctdb, &r->hdr);
313 talloc_free(tmp_ctx);
318 called when a CTDB_REQ_CALL packet comes in
320 void ctdb_request_call(struct ctdb_context *ctdb, struct ctdb_req_header *hdr)
322 struct ctdb_req_call *c = (struct ctdb_req_call *)hdr;
324 struct ctdb_reply_call *r;
326 struct ctdb_ltdb_header header;
327 struct ctdb_call call;
328 struct ctdb_db_context *ctdb_db;
330 ctdb_db = find_ctdb_db(ctdb, c->db_id);
332 ctdb_send_error(ctdb, hdr, -1,
333 "Unknown database in request. db_id==0x%08x",
338 call.call_id = c->callid;
339 call.key.dptr = c->data;
340 call.key.dsize = c->keylen;
341 call.call_data.dptr = c->data + c->keylen;
342 call.call_data.dsize = c->calldatalen;
344 /* determine if we are the dmaster for this key. This also
345 fetches the record data (if any), thus avoiding a 2nd fetch of the data
346 if the call will be answered locally */
348 ret = ctdb_ltdb_lock_fetch_requeue(ctdb_db, call.key, &header, hdr, &data,
349 ctdb_recv_raw_pkt, ctdb);
351 ctdb_send_error(ctdb, hdr, ret, "ltdb fetch failed in ctdb_request_call");
355 DEBUG(2,(__location__ " deferred ctdb_request_call\n"));
359 /* if we are not the dmaster, then send a redirect to the
361 if (header.dmaster != ctdb->vnn) {
362 ctdb_call_send_redirect(ctdb, c, &header);
363 talloc_free(data.dptr);
364 ctdb_ltdb_unlock(ctdb_db, call.key);
368 /* if this nodes has done enough consecutive calls on the same record
369 then give them the record
370 or if the node requested an immediate migration
372 if ( (header.laccessor == c->hdr.srcnode
373 && header.lacount >= ctdb->max_lacount)
374 || c->flags&CTDB_IMMEDIATE_MIGRATION ) {
375 ctdb_call_send_dmaster(ctdb_db, c, &header, &call.key, &data);
376 talloc_free(data.dptr);
377 ctdb_ltdb_unlock(ctdb_db, call.key);
381 ctdb_call_local(ctdb_db, &call, &header, &data, c->hdr.srcnode);
383 ctdb_ltdb_unlock(ctdb_db, call.key);
385 len = offsetof(struct ctdb_reply_call, data) + call.reply_data.dsize;
386 r = ctdb->methods->allocate_pkt(ctdb, len);
387 CTDB_NO_MEMORY_FATAL(ctdb, r);
388 talloc_set_name_const(r, "reply_call packet");
390 r->hdr.ctdb_magic = CTDB_MAGIC;
391 r->hdr.ctdb_version = CTDB_VERSION;
392 r->hdr.operation = CTDB_REPLY_CALL;
393 r->hdr.destnode = hdr->srcnode;
394 r->hdr.srcnode = hdr->destnode;
395 r->hdr.reqid = hdr->reqid;
396 r->status = call.status;
397 r->datalen = call.reply_data.dsize;
398 if (call.reply_data.dsize) {
399 memcpy(&r->data[0], call.reply_data.dptr, call.reply_data.dsize);
400 talloc_free(call.reply_data.dptr);
403 ctdb_queue_packet(ctdb, &r->hdr);
409 called when a CTDB_REPLY_CALL packet comes in
411 This packet comes in response to a CTDB_REQ_CALL request packet. It
412 contains any reply data from the call
414 void ctdb_reply_call(struct ctdb_context *ctdb, struct ctdb_req_header *hdr)
416 struct ctdb_reply_call *c = (struct ctdb_reply_call *)hdr;
417 struct ctdb_call_state *state;
419 state = idr_find_type(ctdb->idr, hdr->reqid, struct ctdb_call_state);
421 DEBUG(0, ("reqid %d not found\n", hdr->reqid));
425 state->call.reply_data.dptr = c->data;
426 state->call.reply_data.dsize = c->datalen;
427 state->call.status = c->status;
429 talloc_steal(state, c);
431 state->state = CTDB_CALL_DONE;
432 if (state->async.fn) {
433 state->async.fn(state);
438 called when a CTDB_REPLY_DMASTER packet comes in
440 This packet comes in from the lmaster response to a CTDB_REQ_CALL
441 request packet. It means that the current dmaster wants to give us
444 void ctdb_reply_dmaster(struct ctdb_context *ctdb, struct ctdb_req_header *hdr)
446 struct ctdb_reply_dmaster *c = (struct ctdb_reply_dmaster *)hdr;
447 struct ctdb_call_state *state;
448 struct ctdb_db_context *ctdb_db;
452 state = idr_find_type(ctdb->idr, hdr->reqid, struct ctdb_call_state);
457 ctdb_db = state->ctdb_db;
459 ret = ctdb_ltdb_lock_requeue(ctdb_db, state->call.key, hdr,
460 ctdb_recv_raw_pkt, ctdb);
465 DEBUG(0,(__location__ " Failed to get lock in ctdb_reply_dmaster\n"));
470 data.dsize = c->datalen;
472 talloc_steal(state, c);
474 /* we're now the dmaster - update our local ltdb with new header
476 state->header.dmaster = ctdb->vnn;
478 if (ctdb_ltdb_store(ctdb_db, state->call.key, &state->header, data) != 0) {
479 ctdb_ltdb_unlock(ctdb_db, state->call.key);
480 ctdb_fatal(ctdb, "ctdb_reply_dmaster store failed\n");
484 ctdb_call_local(ctdb_db, &state->call, &state->header, &data, ctdb->vnn);
486 ctdb_ltdb_unlock(ctdb_db, state->call.key);
488 talloc_steal(state, state->call.reply_data.dptr);
490 state->state = CTDB_CALL_DONE;
491 if (state->async.fn) {
492 state->async.fn(state);
498 called when a CTDB_REPLY_ERROR packet comes in
500 void ctdb_reply_error(struct ctdb_context *ctdb, struct ctdb_req_header *hdr)
502 struct ctdb_reply_error *c = (struct ctdb_reply_error *)hdr;
503 struct ctdb_call_state *state;
505 state = idr_find_type(ctdb->idr, hdr->reqid, struct ctdb_call_state);
506 if (state == NULL) return;
508 talloc_steal(state, c);
510 state->state = CTDB_CALL_ERROR;
511 state->errmsg = (char *)c->msg;
512 if (state->async.fn) {
513 state->async.fn(state);
519 called when a CTDB_REPLY_REDIRECT packet comes in
521 This packet arrives when we have sent a CTDB_REQ_CALL request and
522 the node that received it is not the dmaster for the given key. We
523 are given a hint as to what node to try next.
525 void ctdb_reply_redirect(struct ctdb_context *ctdb, struct ctdb_req_header *hdr)
527 struct ctdb_reply_redirect *c = (struct ctdb_reply_redirect *)hdr;
528 struct ctdb_call_state *state;
530 state = idr_find_type(ctdb->idr, hdr->reqid, struct ctdb_call_state);
531 if (state == NULL) return;
533 talloc_steal(state, c);
535 /* don't allow for too many redirects */
536 if (state->redirect_count++ == CTDB_MAX_REDIRECT) {
537 c->dmaster = ctdb_lmaster(ctdb, &state->call.key);
540 /* send it off again */
541 state->node = ctdb->nodes[c->dmaster];
542 state->c->hdr.destnode = c->dmaster;
544 ctdb_queue_packet(ctdb, &state->c->hdr);
550 static int ctdb_call_destructor(struct ctdb_call_state *state)
552 idr_remove(state->node->ctdb->idr, state->c->hdr.reqid);
558 called when a ctdb_call times out
560 void ctdb_call_timeout(struct event_context *ev, struct timed_event *te,
561 struct timeval t, void *private_data)
563 struct ctdb_call_state *state = talloc_get_type(private_data, struct ctdb_call_state);
564 state->state = CTDB_CALL_ERROR;
565 ctdb_set_error(state->node->ctdb, "ctdb_call %u timed out",
566 state->c->hdr.reqid);
567 if (state->async.fn) {
568 state->async.fn(state);
573 this allows the caller to setup a async.fn
575 static void call_local_trigger(struct event_context *ev, struct timed_event *te,
576 struct timeval t, void *private_data)
578 struct ctdb_call_state *state = talloc_get_type(private_data, struct ctdb_call_state);
579 if (state->async.fn) {
580 state->async.fn(state);
586 construct an event driven local ctdb_call
588 this is used so that locally processed ctdb_call requests are processed
589 in an event driven manner
591 struct ctdb_call_state *ctdb_call_local_send(struct ctdb_db_context *ctdb_db,
592 struct ctdb_call *call,
593 struct ctdb_ltdb_header *header,
596 struct ctdb_call_state *state;
597 struct ctdb_context *ctdb = ctdb_db->ctdb;
600 state = talloc_zero(ctdb_db, struct ctdb_call_state);
601 CTDB_NO_MEMORY_NULL(ctdb, state);
603 talloc_steal(state, data->dptr);
605 state->state = CTDB_CALL_DONE;
606 state->node = ctdb->nodes[ctdb->vnn];
608 state->ctdb_db = ctdb_db;
610 ret = ctdb_call_local(ctdb_db, &state->call, header, data, ctdb->vnn);
611 talloc_steal(state, state->call.reply_data.dptr);
613 event_add_timed(ctdb->ev, state, timeval_zero(), call_local_trigger, state);
620 make a remote ctdb call - async send. Called in daemon context.
622 This constructs a ctdb_call request and queues it for processing.
623 This call never blocks.
625 struct ctdb_call_state *ctdb_daemon_call_send_remote(struct ctdb_db_context *ctdb_db,
626 struct ctdb_call *call,
627 struct ctdb_ltdb_header *header)
630 struct ctdb_call_state *state;
631 struct ctdb_context *ctdb = ctdb_db->ctdb;
633 state = talloc_zero(ctdb_db, struct ctdb_call_state);
634 CTDB_NO_MEMORY_NULL(ctdb, state);
636 len = offsetof(struct ctdb_req_call, data) + call->key.dsize + call->call_data.dsize;
637 state->c = ctdb->methods->allocate_pkt(state, len);
638 CTDB_NO_MEMORY_NULL(ctdb, state->c);
639 talloc_set_name_const(state->c, "req_call packet");
641 state->c->hdr.length = len;
642 state->c->hdr.ctdb_magic = CTDB_MAGIC;
643 state->c->hdr.ctdb_version = CTDB_VERSION;
644 state->c->hdr.operation = CTDB_REQ_CALL;
645 state->c->hdr.destnode = header->dmaster;
646 state->c->hdr.srcnode = ctdb->vnn;
647 /* this limits us to 16k outstanding messages - not unreasonable */
648 state->c->hdr.reqid = idr_get_new(ctdb->idr, state, 0xFFFF);
649 state->c->flags = call->flags;
650 state->c->db_id = ctdb_db->db_id;
651 state->c->callid = call->call_id;
652 state->c->keylen = call->key.dsize;
653 state->c->calldatalen = call->call_data.dsize;
654 memcpy(&state->c->data[0], call->key.dptr, call->key.dsize);
655 memcpy(&state->c->data[call->key.dsize],
656 call->call_data.dptr, call->call_data.dsize);
658 state->call.call_data.dptr = &state->c->data[call->key.dsize];
659 state->call.key.dptr = &state->c->data[0];
661 state->node = ctdb->nodes[header->dmaster];
662 state->state = CTDB_CALL_WAIT;
663 state->header = *header;
664 state->ctdb_db = ctdb_db;
666 talloc_set_destructor(state, ctdb_call_destructor);
668 ctdb_queue_packet(ctdb, &state->c->hdr);
670 event_add_timed(ctdb->ev, state, timeval_current_ofs(CTDB_REQ_TIMEOUT, 0),
671 ctdb_call_timeout, state);
676 make a remote ctdb call - async recv - called in daemon context
678 This is called when the program wants to wait for a ctdb_call to complete and get the
679 results. This call will block unless the call has already completed.
681 int ctdb_daemon_call_recv(struct ctdb_call_state *state, struct ctdb_call *call)
683 while (state->state < CTDB_CALL_DONE) {
684 event_loop_once(state->node->ctdb->ev);
686 if (state->state != CTDB_CALL_DONE) {
687 ctdb_set_error(state->node->ctdb, "%s", state->errmsg);
692 if (state->call.reply_data.dsize) {
693 call->reply_data.dptr = talloc_memdup(state->node->ctdb,
694 state->call.reply_data.dptr,
695 state->call.reply_data.dsize);
696 call->reply_data.dsize = state->call.reply_data.dsize;
698 call->reply_data.dptr = NULL;
699 call->reply_data.dsize = 0;
701 call->status = state->call.status;